A synergic solvent extraction method using 1 -nitroso-2-naphthol and trioctylphosphine oxide (TOPO) in chloroform has been applied to study the carbonate complexes of Eu(III). These studies have been performed at 1.0 Μ ionic strength and at varied total carbonate (SC0 2 = 1χ10~3 -0.5M) concentrations and pH (8.0-9.0). The following species have been identified: EuCOa, EU(C0 3 )J, EU(C0 3 )|~ and Eu(C0 3 )4~; and their formation constants (log/?) have been calculated as 5.88 + 0.05, 10.03 + 0.06,12.4 + 0.08 and 14.3+0.1, respectively. The specific ion interaction theory (SIT) and ion-pairing model have been used to extrapolate the stability constants of EuCOj and EU(C0 3 )2 to zero ionic strength. The corresponding log/? 0 values are 8.06 and 12.91 by SIT and 7.91 and 13.07 by the ionpairing model.

Canadian deuterium uranium (CANDU) pressurized heavy-water reactors produce 14C by neutron activation of trace quantities of nitrogen in annular gas and reactor components (14N(n,p)14C), and from 17O in the heavy water moderator by (17O(n,α)14C). The radiocarbon produced in the moderator is removed on ion exchange resins incorporated in the water purification systems; however, a much smaller gaseous portion is vented from reactor stacks at activity levels considerably below 1% of permissible derived emission limits. Early measurements of the carbon speciation indicated that >90% of the 14C emitted was in the form of CO2. We conducted surveys of the atmospheric dispersion of 14CO2 at the Chalk River Laboratories and at the Pickering Nuclear Generating Station. We analyzed air, vegetation, soils and tree rings to add to the historical record of 14C emissions at these sites, and to gain an understanding of the relative importance of the various carbon pools that act as sources/sinks within the total 14C budget. Better model parameters than those currently available for calculating the dose to the critical group can be obtained in this manner. Global dose estimates may require the development of techniques for estimating emissions occurring outside the growing season.

Migration behavior of Eu(III) in sandy soil in the presence of dissolved organic material (DOM) was studied by the column experiments using a constant feed technique. A site specific DOM, isolated from the groundwater at Chalk River in Canada, a reagent humic acid (HA) from Aldrich Co. Ltd. and Suwannee River HA and River fulvic acid (FA) from the International Humic Substances Society, as reference materials, were used in this study for comparing their effects on the mobility of Eu(III). Solutions of 152 Eu in the presence of the DOMs at pH 5.5 and ionic strength of 0.01 Μ NaC10 4 were introduced onto the column (2.5 cm I.D. X 2.5 cm long) packed with the sandy soil at a constant flow rate of 1.0 mL · min -1 . In the absence of DOM, Eu was not detected even after 90 pore volumes were eluted from the column. Europium elution was observed, however, when any of the DOMs were present. Maximum relative concentrations of Eu were observed in the order: River FA < Groundwater DOM < River HA = Aldrich HA. This sequence suggests that differences in characteristics of DOM may be reflected in mobility of Eu-DOM complexes in sandy soil.

No abstract

Residues of polychlorinated biphenyls (PCBs) and organochlorine pesticides were determined in several species of commercial fish from the Great Lakes and compared to the total organic chlorine determined by neutron activation analysis. The mean organochlorine contents ranged from 44 to 138 ppm (lipid basis) and were 5 to 72 times higher than the contents of PCBs and organochlorine pesticides. Marine fish also contained a large proportion of unidentified organic chlorine. The unknown material in the Great Lakes fish was found to chromatograph with the high molecular weight lipid fraction by gel permeation chromatography.